Copolymers of vinyl halides, vinylidene halides and various phosphorus-containing vinyl monomers have been frequently used as fire retardant agents for various flexible flammable materials, such as paper, cotton fabrics and non-woven compositions. For light weight and flexible materials, there is a limit to how much polymer can be incorporated therein before a soft hand and flexibility are lost. When insufficient polymer is incorporated, the material will not be flame retardant.